Electronic Scattering and Spin Disorder in 3d-FERROMAGNETS in the Paraprocess Regime

We determine the collective spin excitations and their contribution to the intrinsic resistivity in 3d-ferromagnets by high field magneto-transport experiments. In the paraprocess regime, the longitudinal magneto resistance has a non saturating negative slope of about 0.02-0.05μΩ.cm.T^-1 at 300 K for Fe, Co and Ni. We demonstrate its magnetic origin and assign the effect to a decrease of the electron-magnon scattering due to the damping of spin waves in high field. We provide a unique estimate of the pure magnetic resistivity in 3d-ferromagnets. Our analysis also gives an insight into the low energy spin waves, i.e. the theoretical magnon saturation field and the magnon mass renormalization.